The invention pertains to a precision casting system with a gas-tight furnace chamber with a lock provided with two sealing plates; with a melting furnace inside the furnace chamber; and with a casting mold carrier, which can be driven into the furnace chamber through the lock in the horizontal direction into a casting position.
In the majority of cases, precision casting systems have a vertically movable casting mold carrier, which can be driven into the casting position by means of a vertically oriented hydraulic cylinder or a threaded spindle. Because of the additive effect of the construction height and the travelling distances, this so-called vertical drive leads to an extremely tall system. As a result, the vertical drive is usually installed in a pit underneath the furnace chamber. This leads to relatively high construction and operating costs, because the vertical drive is poorly accessible to maintenance personnel. .A precision casting system of this type is known from DE-OS 32, 20, 744.
Insofar as a precision casting system of this type is equipped with a heating chamber for "oriented solidification", the casting mold is lowered out of the heating chamber by the creeping motion of the vertical drive, during which the casting mold is unavoidably subject to vibrations, which can have a disadvantageous effect on the microstructure of the casting. The vertical drive has been retained primarily because, with it, it is possible achieve a very a high degree of precision with respect to the positioning of the casting mold carrier together with the casting mold in the pouring range of the melting furnace so that casting can be carried out effectively.
The experts, however, have already experimented with horizontally driven casting molds.
A precision casting system in which a support plate carrying a mold can be driven along a rollway and through a lock into an evacuated furnace chamber is known from DE-AS 10,60, 557. In this case, however, the casting mold must be positioned manually, because it is possible neither to position the casting mold precisely on the support plate nor to bring the support plate without further measures into a precise casting position. The known precision casting furnace is not suitable for automated series production, and it cannot be converted to such use without significant modifications to the transport system. In addition, the known precision casting furnace cannot be retrofitted with a device for bringing about oriented solidification. The invention proceeds from a precision casting system of this type.
A melting and casting system is known from U.S. Pat. No. 3,554,268, but this system is used for the refining of steel and for ingot casting, not for the production of precision castings. In the known device, a battery of ingot molds can be driven up by means of a first truck to a first lock door in a direction parallel to the door. The ingot molds rest on a second truck equipped with an electric motor and are driven over a series of rail segments into a casting chamber, which is separated from the furnace and melting chamber by a second lock gate. The rails of the first and second trucks extend at a right angle to each other. With the known device, it not possible to drive the ingot molds into the casting position. Instead, a transport ladle can be driven along upper rail segments, which are located above and parallel to the lower rail segments. These upper rail segments are divided into sections by the lock gates. Although the ladle itself can be brought into a casting position, it serves merely to transport the melt in portions to the individual ingot molds. Because the upper rail segments are interrupted at two points by the lock gates, a continuous railway must be produced by additional rail segments, which can be swung into position. The known system is not suitable for the production of precision castings and cannot be converted in such a way that a process of oriented solidification could be accomplished. Because of the extreme height of the ingot molds, this known system is two storeys tall even though there is no vertical drive present; that is, the furnace chamber is located on an elevated platform. The construction is in any case extremely complicated in this case as well.
U.S. Pat. No. 3,847,203 discloses stationary casting mold carrier which can be installed right in the furnace chamber of a precision casting system without lock devices. This carrier, including the casting mold, is surrounded by a heating chamber, which is suspended with the option of vertical movement for the purpose of oriented solidification. In this device, which should be described as a laboratory system, the problem of having to drive movable casting mold carriers with casting molds in the horizontal direction precisely into a casting position does not arise; the casting position is defined in advance by the stationary installation of the casting mold carrier. This system is also unsuitable for the automated production of large numbers of precision castings.